1. Field of the Invention
The present invention relates to a torsional vibration monitoring apparatus in which a torsional vibration generated in a rotating shaft system of such as turbine generator is measured at a certain position of the shaft system at which the measurement is possible and a vibration of the shaft system at an arbitrary position thereof is estimated from the vibration measured.
2. Description of the Prior Art
It is very important in designing a rotating shaft system of such as turbine generator, compresser or marine diesel engine to know various disturbances applied thereto. Particularly, it is very important to operators thereof to know the fatigue life of the system which may vary time to time with the disturbances.
It is well known that the rotating shaft system of, for example, the turbine generator is very long and sometimes it becomes several tens meters. Therefore, the number of points at which the rotating shaft system is to be monitored is usually several.
Furthermore the torsional vibration of the rotating shaft system may provide, fatigue damages to the shaft and therefore it is important to measure the vibration. However, a provision of torsional vibration measuring devices at several points along the shaft system is economically disadvantageous and in some cases, it may be physically impossible to locate those measuring devices.